Section 5 Machinery

501. General

Machinery installations of the ship are to be in accordance with this section in addition to Ch 3, Sec 4.

502. Supporting machinery and systems

1. Power System

(1) Crane with self-contained or independent power plant :

(A) Where the crane is fitted with self-contained or independent power plant with the prime mover and its auxiliary systems including the power take-off means and the starting system, the power plant is to be sized such that the minimum required hook velocity can be ach- ieved when lifting the corresponding rated load, taking into account simultaneous operations (hoist, luff, swing) requirements, efficiencies of the power plant and the system components.

(B) Gasoline engines as prime movers are prohibited.

Engine exhausts are to be equipped with spark arrestors and all exhaust systems are to be guarded in areas where contact by personnel in the performance of their normal duties is possible.

(C) Fuel tanks fills and overflows are not to run close to exhausts. Fuel tanks are to be equip- ped with filler necks and caps designed to prevent fuel contamination from external sources. Removable caps, where fitted, are to be securely tethered to the filler.

(2) Cranes driven by vessel’s power systems :

Where the crane is driven by vessel’s power systems, either hydraulic or electric, the vessel’s main power plant is to be sized with sufficient capacity to operate the crane under the load conditions defined in (1) and arranged to ensure the functioning of all safety equipment and es-

34 Guidance for Offshore Support Vessels 2015

and degraded.

2. Heeling and ballasting systems

(1) Where heeling systems are provided to counteract the crane’s overturning moment, the systems are to be designed to ensure that the vessel is capable of withstanding the sudden loss of the hook load in each condition of loading and operation.

(2) The free surface effects are to be considered for those tanks which are ballasted.(Refer to 203.

2. (2)).

3. Controls and communications

(1) Controls

(A) All controls used during the normal crane operating cycle are to be located within easy reach of the operator while at the operator’s station.

(B) Control levers for boom hoist, load hoist, swing and boom telescope (when applicable) are to be returned automatically to their center (neutral) positions on release. Control operations and functions are to be clearly marked and easily visible by the operator at the operator’s control station.

(C) As appropriate, monitoring is to be provided to indicate availability of power, air pressure, hy- draulic pressure, motor running and slewing brake mechanism engagement.

(D) Cranes are to be provided with an overload-protection system. Motor running protection is to be provided and is to be set between 100% and 125% of motor rated current.

(E) Provisions are to be made for emergency stop of the crane operations by the operator at the operator’s control station.

(2) Communications

Hard-wired communications is to be provided between the crane operator’s control station and the vessel’s station keeping control station.